Practice projectile



March 18, 1969 E. JOCH 3,433,157

PRACTICE PROJECTILE Filed Dec. 50, 1966 INVENTOR ERICH JOCH ATTORNEYSUnited States Patent 3,433,157 PRACTICE PROJECTILE Erich Joch,Bensberg-Refrath, Germany, assignor to Dynamit Nobel Aktiengesellschaft,Troisdorf, Germany Filed Dec. 30, 1966, Ser. No. 606,162 Claimspriority, application Germany, Dec. 31, 1965,

D 49,056 US. Cl. 102-927 Int. Cl. F42b 11/18, 13/20 12 Claims ABSTRACTOF THE DISCLOSURE The present disclosure relates to a practiceprojectile that will fire from the barrel of a weapon in the manner oflive ammunition, will partially disintegrate upon ejection from thebarrel, hit the target with a simulated live projectile, and have agreatly reduced range of danger. The projectile includes a large calibreprojectile that will readily disintegrate upon leaving the correspondingcalibre barrel of the weapon and a small calibre projectile that will beguided along and projected from a sub-calibre barrel centrally arrangedwithin the large calibre projectile. The small calibre projectile willreceive its motive force through orifices in the rear of the largecalibre projectile from the propellant gases so that it will leave thesubcalibre barrel around the time that the large calibre projectileleaves the barrel of the weapon. The rigid, small calibre projectilewill then travel the trajectory to strike the target to simulate theeffect of live ammunition. Preferably, the large calibre projectile isconstructed with an outer thin walled case and inner sub-calibre barrelforming tube of a synthetic polymer; the space between these twoelements is filled with particulate material.

Background of the invention In training troops, particularly in peacetime, it is desirable to provide ammunition for target practice, thatis, ammunition that will produce a projectile for striking the target.It is also desirable to have the range of danger substantially reducedas compared to the shooting of live or normal-type ammunition andfunction in an automatic weapon substantially the same as liveammunition in regard to barrel recoil, cadence, muzzle blast, muzzleflash, etc.

It is known in the prior art to provide target projectiles, particularlyconstructed from synthetic resin or synthetic polymers, for shooting ina danger range that is substantially reduced as compared to liveammunition. While the desired result of a reduced range is obtained withthis type of prior art projectile, the desired above-mentioned effectswithin the weapon, particularly a heavy automatic weapon with automaticrecoil mechanisms, is either not obtained or at best obtained only to anunsatisfactory degree usually as a result of additional complex andexpensive modifications of the weapon. In addition, it is known in theprior art to provide a disintegrating type projectile that will producethe desired above-mentioned effects within the barrel of the weapon, butno impact effect is produced with a target because the projectiledisintegrates to a large degree while still within the barrel or shortlybefore emerging from the barrel. Both of the above-mentioned prior arttypes of projectiles do not satisfy the requirements of a targetprojectile for shooting within a reduced danger range, as compared tolive ammunition, to strike a target and also assure the automaticoperation of an automatic operation of an automatic weapon, par of anautomatic weapon, particularly with automatic recoil mechanisms, aswould be done with live ammunition. Therefore, it is seen that there arebasically two desirable categories of effects or requirements for atarget projectile that has been satisfied singly by the prior art, butthat have not been satisfied by a single prior art projectile. It is anobject of the present invention to provide a pro jectile that willsatisfy these heretofore conflicting requirements or effects in a simpleand economical manner.

Brief description of the invention The above-mentioned disadvantages andthe above-mentioned requirements have been satisfied with the projectileof the present invention that employs a relatively large calibreprojectile having an outer synthetic polymer thin walled case and aninner thin walled synthetic polymer tube, with the space therebetweenfilled with particle type material, preferably metal powder, metalshavings, or the like that are usually disintegrated under the largeforces encountered during firing shortly before the projectile leavesthe barrel of the weapon or shortly thereafter. The tube is centrallylocated to form a central axial sub-calibre barrel open at the forwardend and covered at the rear end except for relatively small orifices orapertures to throttle and admit propellant gases into the rear end ofthe subcalibre barrel. A sub-calibre or relatively small calibre solidprojectile or live ammunition is provided in the rear end of thesub-calibre barrel; the small calibre projectile may be constructed ofmetal, a synthetic polymer or other suitable materials.

The relatively large, heavy projectile of the present invention willcompletely assure the automatic operation of the weapon, particularly aweapon having automatic recoil mechanisms, because the projectile may bedesigned to have the same weight and other barrel characteristics as thelive ammunition designed for the weapon. On the other hand, the insertedrelatively small calibre solid projectile will be guided by andprojected from the subcalibre barrel of the large calibre projectile toproduce an impact effect upon the target to truly simulate the liveammunition only within a substantially reduced danger range as comparedto the live ammunition designed for the weapon.

Preferably, the projectile is designed so that the small calibre solidprojectile is carried within the readily disintegratable large calibreprojectile to within a short distance from the front of the weaponmuzzle before it begins its own free flight after leaving thesub-calibre barrel of the large calibre projectile. Therefore, with thispreferred construction it is assured that the small calibre projectile,which is very light when compared with the live projectile designed forthe weapon, is securely guided within the weapon barrel up to about themuzzle thereof. Thus, there is no danger that the small calibre solidprojectile will be deflected from its predetermined flight trajectory bypassing gases while still being contained within the barrel of theweapon, which might result that it is struck against the inner weaponbarrel wall where it could be smashed. According to a more narrow aspectof the present invention, the sub-calibre barrel may be provided withrifling or guiding grooves for rotating the small calibre projectile toimprove its stability during flight. Broadly, the larger calibreprojectile may be constructed as a unitary or multi-part readilydisintegratable body so that these grooves may be made directly in thewalls forming the sub-calibre barrel to thus eliminate any speciallining or tube for the sub-calibre barrel. Preferably, thedisintegratable charge is loosely accommodated within a thin-walledchamber producing a lining for the subcalibre barrel, which may beprovided with the rifling or grooves mentioned above. Preferably thischamber and sub-calibre barrel is formed with a thin-walled syntheticpolymer tube for construction economy and improved stability within theweapon barrel. Preferably, the small calibre projectile is provided witha coating of soft material, particularly a soft synthetic polymer, sothat it will readily interengage with the grooves of the sub-calibrebarrel to assure the faultless rotation of the small calibre projectileby the rifiing.

The propulsion of the small calibre solid projectile in the sub-calibrebarrel of the readily disintegratable large calibre projectile may beinfluenced to a large extent and in the desired manner by appropriatelydimensioning the orifice means or bores in the bottom of the largecalibre projectile case to correspondingly change the throttling of thepropulsion gases into the sub-calibre barrel. Additional bores may beprovided for introducing propellant gases into the rear end of thesub-calibre bore; particularly desirable results are obtained when thesebores open into the side walls of the sub-calibre barrel immediatelyadjacent the sealing portions of the small calibre solid projectile sothat these bores are not opened for conducting gases until the smallcalibre projectile has moved forwardly a substantial distance in thesub-calibre barrel. Also, these bores may be rendered inoperative untila predetermined time after ignition, by providing a delay combustiblecomposition that will burn off at a controlled desired rate to open thebore for the passage of propellant gases into the sub-calibre barrelafter a desired controlled delay period of time. Therefore, thepropulsion characteristics of the sub-calibre or small calibreprojectile may be accurately adjusted and controlled.

An example of a synthetic polymer is polyvinyl chloride. As mentioned inthe specification, various elements of the present invention may beconstructed of a synthetic polymer for ease of molding, destructibility,economy and efficiency.

Additional objects, features, advantages and embodiments of the presentinvention will become more apparent from the following description ofthe drawing.

Brief description of the drawing The single figure in the attacheddrawing illustrates a preferred embodiment of the present invention.

Detailed description of the invention The target projectile of thepresent invention consists of a relatively large calibre readilydisintegratable projectile and a relatively small calibre relativelyrigid projectile contained therein.

The relatively large calibre projectile comprises an outer syntheticpolymer case 1 that has a plurality of sealing rings on its outerperiphery adjacent it rear end for providing sealing engagement with thewalls of the weapon barrel to prevent the escape of the propulsion gasespast the projectile. The forward end of the case 1 is closed with andsealed with the forward end of a synthetic polymer thin-walled tube 2,which forms the sub-calibre barrel for guiding the small calibreprojectile. At the rear end, the tube 2 and case 1 are closed by a coveror caplike constructed bottom 7 except for an axially extendingcentrally located orifice or bore 8 communicating with the sub-calibrebarrel. The space or chamber formed by the case 1, tube 2, and bottom 7is filled with loose particles of relatively heavy material, forexample, metal shavings, which are at most only loosely bonded together.Preferably, this particle material is bonded into several separateannular blocks 6. An additional orifice or bore 9 is provided to extendat an angle through the bottom 7, the rearmost portion of the particlematerial 6 and the side wall of the tube 2 to provide communicationbetween the outside rear of the projectile and the rear interior of thesub-calibre barrel; this bore 9 is filled with a delaying compositionthat will burn upon ignition to open up the bore after a controlledperiod of time after ignition. The tip or forward end of the projectileis reinforced by an integral molded thickening of the synthetic polymercase 1 as shown at 4 or alternatively by a separate synthetic polymerinsert as shown in the left-hand side opposite the reinforcement 4;thus, two embodiments have been shown in the drawing for purposes ofsimplicity.

The relatively small calibre solid projectile 5 is accommodated withinthe rear end of the sub-calibre barrel formed by the tube 2. Theprojectile 5 is formed as a conventionally shaped projectile and may beconstructed of a synthetic polymer, metal or like material.

Upon ignition, the propellant gases which develop from the ignitedpropellant charge (not shown) will form hehind the projectile to drivethe projectile, that is, the large calibre projectile and small calibreprojectile as a unit, forwardly in the barrel of the weapon (not shown)by the reaction of the pressure against the bottom 7. An amount of thepropellant gas that is determined by the size and shape of thethrottling bore 8 enters the rear end of the sub-calibre barrel at acontrolled rate to thereby drive the small calibre solid projectile 5forwardly within the sub-calibre barrel formed by the tube 2. Thepropulsion of the small calibre projectile may be adjusted and varied bya suitable design of the orifice 8. In the meantime, the delayingcomposition within the slanted bore 9 is ignited and burns over apredetermined delay period, after which the bore 9 is opened to allowthe entrance of the hot propellant gases, which will then provide anadditional impulse to the bullet 5 for its desired final projection fromthe sub-calibre barrel. It is highly advantageous to provide the openingof the slanted bore 9 adjacent the sealing surface of the small calibreprojectile 5 so that this bore 9 will not be opened until the smallcalibre projectile 5 has moved a substantial distance forwardly in thesub-calibre barrel formed by the tube 2.

In order to assure, on the one hand, that the small calibre projectile 5is guided over the entire length of the weapon barrel but will not bedeflected, on the other hand, from the predetermined flight path ortrajectory thereof as a result of the subsequent disintegration of thereadily disintegratable large calibre projectile, care must be takenthat the conditions and construction are such that the small calibreprojectile 5 will emerge from the sub-calibre barrel formed by the tube2 shortly before the large calibre projectile projectile leaves theweapon barrel and disintegrates, according to the most preferredembodiment of the present invention. This action will be enhanced by thepropellant gases still present in the sub-calibre barrel when thereadily disintegratable large calibre projectile emerges from the muzzleof the weapon and, respectively, by the propellant gases passingtherethrough. Also, it is preferable that the large calibre projectileand the relatively small calibre projectile 5 together close off thebarrel of the weapon (not shown) with respect to the propellant gasesuntil the projectiles have arrived approximately at the muzzle of theweapon so that the pressure of the propellant gases will act with theirfull force for the propulsion of the movable parts, that is, provide thenecessary recoil for the actuation of the automatic mechanisms of theautomatic weapon, particularly a heavy automatic weapon. Independentlyof these characteristics, it is possible to influence or adjust to arelatively large degree and in the desired accurate manner the flightrange or trajectory of the small calibre projectile 5 by correspondingdesign or choice of the associated structure, for example, by acorrelation between the cross-sectional dimensions of the relativelylarge calibre projectile and the relatively small calibre solidprojectile 5, by the dimensions of the bore or orifice 8, by the numberand dimensions of the bores or orifices 9, by the placement of the bores9, by the selection of the delaying composition within the bore 9, andby a selection of the particular material used to construct therelatively small calibre projectile 5 to change its weight.

The above described preferred embodiment and variations have been setforth merely as illustrative examples of the present invention andadditional variations, modifications, embodiments and the like arecontemplated within the spirit and scope of the present invention asdefined by the following claims.

I claim:

1. A practice projectile with an axis for practice firing from thenormal barrel of a firearm in its axial direction under the infiuence ofa separate motive force to strike a target within a reduced danger rangeand produce barrel firing efiects substantially the same as liveammunition, comprising: large caliber projectile means of readilydestnuctible construction for firing and for thereafter disintegratingwithin the close proximity of the firearm muzzle before striking atarget; small caliber projectile means of relatively rigid construction,with respect to said large caliber projectile means, mounted within saidlarge caliber projectile means for separating from said large caliberprojectile means after firing to travel intact separately to the targetindependently of said large caliber projectile means; said large caliberprojectile means having a central sub-caliber barrel means extending inthe axial direction at least twice as far as said small caliberprojectile means and being of uniform diameter substantially equal tothe external diameter of said small caliber projectile means for guidingsaid small caliber projectile means; said small caliber projectile meansbeing mounted in said sub-caliber barrel means.

2. The device of claim 1, said sub-calibre barrel means extendingforwardly without restriction to and opening to the atmosphere at theforwardmost axial end of said large calibre projectile means; saidsub-calibre barrel means extending rearwardly substantially withoutrestriction to within close proximity to the rearwardmost axial end ofsaid large calibre projectile means for guiding said small calibreprojectile means during its separation from said large calibreprojectile; said small calibre projectile means being mounted in therearmost portion of said sub-calibre lbarrel; said large calibreprojectile means having orifice means forming flow restricting gaspassage for establishing fluid communication between said sub-calibrebarrel rearwardly of said calibre projectile means and the exterior ofthe projectile at its rearward end, and for throttling the propulsiongases for said large calibre projection means and conducting them to therear of said small calibre projectile means for providing the motiveforce to propel said small calibre projectile means forwardly along andout of said sub-calibre barrel.

3. The device of claim 2, said orifice means including a plurality ofbores uniformly distributed around and extending completely through therear portion of said large calibre projectile means.

4. The device of claim 2, said orifice means including at least one borebeing filled with a com bustile composition means for closing thecorresponding bore only for a predetermined time after initial firing ofthe projectile to conduct propellant gases to said small calibreprojectile means only after said large calibre projectile means hasmoved at least a substantial distance forwardly in the said sub-calibrebarrel.

5. The device of claim 2, said orifice means including at least onepassage means extending completely through the rear portion of saidlarge calibre projectile means and having an opening in said sub-calibrebarrel means immediately adjacent and aligned with the sealing portionof said small calibre projectile for conducting propellant gases intosaid sub-calibre barrel means only after said small calibre projectilehas moved a substantial distance forward within said sub-calibre barrelmeans to open said opening.

6. The device of claim 2, a plurality of rifling groove means on theinside of said sub-calibre barrel means for rotating said small calibreprojectile means to improve its stability during flight.

7. The device of claim 6, said small calibre projectile means having acoating on its exterior that is substantially softer than the remainderof said small calibre projectile means.

8. The device of claim 2, wherein said large calibre projectile meanscomprises a substantially tubula relatively thin-walled syntheticpolymer case closed at one end except for said sub-calibre barrel means;a synthetic polymer relatively thin walled tube forming said sub-calibrebarrel means; additional synthetic polymer material between said caseand tube in the vicinity of and reinforcing the forwand end of saidlarge calibre projectile means; means closing the rearward end betweensaid tube and said case; particulate material at most loosely boundtogether filling substantially the entire space between said case, saidtube and said closing means; and synthetic polymer annular sealing ringmeans on the circumferential exterior of said case for providing annularsealing engagement with the barrel of the weapon.

9. A practice projectile with an axis for practice firing from thenormal barrel of a firearm in its axial direction under the influence ofa separate motive force to strike a target within a reduced danger rangeand produce barrel firing eifects substantially the same as liveammunition, comprising: large caliber projectile means of readilydestructible construction 'for firing and for thereafter disintegratingwithin the close proximity of the firearm muzzle [before striking atarget; small caliber projectile means of relatively rigid construction,with respect to said lange caliber means, mounted within said largecaliber projectile means for separating from said large caliberprojectile means after firing to travel intact separately to the targetindependently of said large caliber projectile means; said large caliberprojectile means having a central sub-caliber barrel means extending inthe axial direction and being of uniform diameter substantially equal tothe external diameter of said small caliber projectile means for guidingsaid small caliber projectile means; said small caliber projectile meansbeing mounted in said sub-caliber barrel means; said large caliberprojectile means comprises a substantially tulbular relativelythin-walled synthetic polymer case closed at one end except for saidsub-caliber barrel means; a synthetic polymer relatively thin-walledtube forming said sub-caliber barrel means; additional synthetic polymermaterial between said case and tube in the vicinity of and reinforcingthe forward end of said large caliber projectile means; means closingthe rearward end between said tube and said case, particulate materialat most loosely bound together filling substantially the entire spacebetween said case, said tube and said closing means; and syntheticpolymer annular sealing ring means on the circumferential exterior ofsaid case for providing annular sealing engagement with the barrel ofthe weapon.

10. A practice projectile with an axis for practice firing from thenormal barrel of a firearm in its axial direction under the influence ofa separate motive force to strike a target within a reduced danger rangeand produce lbarrel firing effects substantially the same as liveammunition, comprising: large caliber projectile means of readilydestructible construction for firing and for thereafter disintegratingwithin the close proximity of the firearm muzzle before striking atarget; small caliber projectile means of relatively rigid construction,with respect to said large caliber means, mounted within said largecaliber projectile means for separating from said large caliberprojectile means after firing to travel intact separately to the targetindependently of said large caliber projectile means; said large caliberprojectile means having a central subcaliber Ibarrel means extending inthe axial direction and (being of uniform diameter substantially equalto the external diam eter of said small caliber projectile means forguiding saidsmall caliber projectile means; said small caliberprojectile means being mounted in said sub-caliber barrel means; aplurality of rifling groove means on the inside of said subcaliberbarrel means for rotating said small caliber projectile means to improveits stability during flight.

11. The device of claim 10, said small calibre projectile means having acoating on its exterior that is substantially softer than the remainderof said small calibre projectle means.

12. The device of claim 11, wherein said large calibre projectile meanscomprises a substantially tubular relatively thin-walled syntheticpolymer case closed at one end except for said sub-calibre barrel means;a synthetic polymer relatively thin walled tube forming said subcali'brebarrel means; additional synthetic polymer material between said caseand tube in the vicinity of and reinforcing the forward end of saidlarge calibre projectile means; means closing the rearward end betweensaid tube and said case; particulate material at most loosely boundtogether filling substantially the entire space between said case, saidtube and said closing means; and synthetic polymer annular sealing ringmeans on the circumferential exterior of said case for providing annularsealing engagement with the barrel of the weapon.

References Cited UNITED STATES PATENTS 3/1957 Alderson 10241 1/1958Beeuwkes et a1 102--91 X 4/1963 Brandt 102-41 2/1965 Jungermann et a1102--91 FOREIGN PATENTS 5/1953 France.

US. Cl. X.R.

